Key Rules at a Glance
Los Angeles distinguishes ADUs approved under its local ordinance from units protected by specific state-law provisions. Those paths have different size and development standards; they are not interchangeable.[7][13]
| Planning question | Starting point |
|---|---|
| How large can a detached ADU be? | The City's ordinance path allows up to 1,200 square feet, subject to applicable site standards. The state-law detached ADU path protects a unit of up to 800 square feet with its own conditions.[7][13] |
| What about side and rear setbacks? | Four feet is the usual starting point for new construction. Qualifying conversions have different treatment; fire and safety requirements still matter.[7][13] |
| Is parking always required? | No. State-law units and several other qualifying situations are exempt. Check the project's permit path before reserving space for parking.[7] |
| Can I build two stories? | Potentially. The unit type, applicable height limit and site determine what is possible, not a citywide promise of a second story.[7] |
| Which office handles the project? | Start with the Los Angeles Department of Building and Safety (LADBS); City Planning and other agencies may also need to review specific conditions.[7] |
Number of ADUs Allowed in the City of Los Angeles
How many ADUs can I build on a single-family lot?
Under the state-law combination, a qualifying lot can accommodate one ADU within eligible existing or proposed space, one JADU and one newly constructed detached ADU. The detached state-law unit is limited to 800 square feet. Each unit must meet the requirements of its category; this is not permission to build three unrestricted backyard homes.[7][13]
A junior accessory dwelling unit (JADU) is a smaller unit of no more than 500 square feet within a single-family residence. Its rules differ from a full ADU's, including requirements related to its layout and use. Confirm the JADU requirements separately rather than applying a full ADU's rules to it.[13]
What about multifamily properties?
On a lot with an existing multifamily dwelling, the state-law path allows up to eight detached ADUs, but no more than the number of existing dwelling units on the lot. On a lot with a proposed multifamily dwelling, the corresponding allowance is up to two detached ADUs.[7][13]
Eligible non-livable space within an existing multifamily building can also be converted: at least one ADU must be allowed, with an allowance of up to 25% of the existing units. Confirm the allowable combination and physical layout for your building before choosing plans.[7][13]
ADU Size & Building Constraints
How large can a detached ADU be?
Los Angeles lists a 1,200-square-foot maximum for detached ordinance ADUs. Lot coverage, floor-area limits and other applicable standards can affect the design. A qualifying 800-square-foot state-law ADU follows a separate protected path; 800 square feet is not a blanket statewide maximum for every ADU.[7][13]
How large can an attached ADU be?
An attached addition and an ADU created within existing space are not the same permit category. The City's guidance recognizes protected attached-unit sizes of 850 square feet, or 1,000 square feet for more than one bedroom, and distinguishes them from other ordinance limits. Ask the designer and LADBS to identify the applicable category before relying on a percentage of the main home's size.[7]
What height and number of stories are allowed?
There is no single height limit for every Los Angeles ADU. The City's guidance distinguishes detached state-law units, attached units and ordinance ADUs. Transit proximity, the existing building and local zoning can change the applicable limit.[7]
If a second story is important to your project, establish the height allowance early. A qualifying unit count does not by itself establish that stacked units or a particular two-story design will fit.
Can I add a roof deck or connect units?
Treat roof decks, exterior stairs and connections between units as design questions to resolve during feasibility, not automatic additions to an approved floor plan. They can affect height, setbacks, access and how the proposed units are classified. Show the entire arrangement on the plans for review.
ADU Setbacks in the City of Los Angeles
How far must the ADU be from the property lines?
New ADUs generally start with four-foot side and rear setbacks. Qualifying conversions of existing space are treated differently, with fire and safety requirements still applying. Do not assume a garage's existing position makes every proposed expansion acceptable.[7][13]
Is there a universal six-foot separation from the main house?
Do not use a Los Angeles County rule as the City's requirement. City Planning's guidance says the zoning passageway and space-between-buildings regulation does not apply during ADU approval or construction. Building-code and fire-safety requirements still need review. Have the design team establish the separation required for the actual structures.[7]
Can an ADU go in the front yard?
It is not a blanket yes or no. The local ordinance generally places detached ADUs behind the primary residence, with exceptions. The City's guidance also recognizes state protections where front setbacks would prevent a qualifying 800-square-foot ADU. Ask LADBS to evaluate the parcel and permit path before ruling a location in or out.[7][13]
The Los Angeles ADU Permit Process
1. Confirm the parcel and the permit path
Check the jurisdiction, zoning, existing buildings and any hillside, fire-hazard, historic or coastal conditions. Identify whether the proposed unit follows the City's ordinance or a state-law ADU category.[7]
2. Prepare a coordinated set of plans
Develop the site layout, floor plans, structural design and energy documentation together. Resolve access, utilities and any site-specific reports before submitting an incomplete design for review.
3. Submit to LADBS and obtain required reviews
Follow LADBS's current submission instructions for your project type. Plan review can involve zoning, building safety and other agencies. Coastal properties may need a separate City Planning review; a geotechnical issue is not, by itself, the same as a coastal permit requirement.[7]
4. Respond to corrections and obtain permits
Address the reviewers' comments, coordinate any required clearances and pay applicable fees. An application or correction response is not an issued construction permit.
5. Build to the approved plans and complete inspections
Arrange the required inspections during construction and confirm the final approvals required before occupancy. Keep permit review, construction and occupancy approval as separate milestones.
How long does approval take?
There is no reliable one-size-fits-all project timeline. City guidance describes a 60-day approve-or-deny period for a complete ADU application, with qualifications, including applications submitted with a new primary dwelling. This is not a promise of an issued permit, finished construction or occupancy within 60 days. Application completeness, corrections and project-specific approvals affect the path.[7]
Parking for Los Angeles ADUs
Will I need another parking space?
Not necessarily. Qualifying state-law ADUs do not require parking. For an ordinance ADU, the City's guidance lists one space unless an exemption applies. Examples include a location within one-half mile walking distance of a bus or rail stop, within one block of a designated car-share pickup or drop-off location, or in an applicable historic district. Other exemptions cover eligible units within existing or proposed space and situations involving unavailable on-street parking permits.[7]
The parking transit test is not the same as the transit test for additional building height. Confirm the correct test for each decision. Coastal properties also need review for Coastal Act requirements.[7]
Must I replace parking removed for an ADU?
The City's guidance provides that replacement parking is not needed when a garage, carport, covered parking structure or uncovered parking space is removed in conjunction with ADU construction. Confirm that the demolition and ADU applications are coordinated and document the applicable exemption.[7]
Where should a required space go?
Have the site plan show any required parking and driveway access. Confirm the proposed location during plan review rather than assuming a setback area or existing driveway automatically qualifies.
Additional Requirements & FAQs
Will my ADU need solar panels?
For permit applications submitted on or after January 1, 2026, the 2025 California Energy Code applies. Newly constructed detached ADUs generally require solar PV, subject to applicable exceptions. The new-construction PV requirement does not apply to additions or alterations; the project's classification matters.[5][6]
Have your energy consultant document the applicable requirements and any exception. A conversion is not a reason to skip energy compliance, and performance modeling is not a blanket exemption from solar.[6]
Do I need a soils report, survey or stormwater plan?
Confirm the required site documentation with the reviewing departments. Existing conditions, slope, drainage and the proposed work can affect the scope. Establish those requirements before commissioning reports; a general city guide cannot determine what your parcel needs.
Do coastal, hillside or historic properties follow different rules?
They can involve additional questions. City guidance distinguishes coastal permitting and restrictions that apply to some ordinance ADUs from the protections for state-law units. Neither a blanket ban nor a blanket exemption is a sound starting point. Identify the site's designations and the proposed ADU category together.[7]
Will the ADU need separate utility meters or a new address?
Confirm service, meter and address requirements with LADBS and the relevant utility providers for the proposed arrangement. Include any service changes in your project scope; do not assume the existing connections will be adequate.
Can I use gas appliances?
Confirm the applicable energy, building and local requirements before selecting appliances or planning gas service. The energy compliance path and project scope matter. Do not rely on an older guide's blanket statement that every new ADU must use, or may use, gas.
Can I use the ADU as a vacation rental? Will rent control apply?
Do not base the project budget on short-term rental income without confirming the permitted use. Rental restrictions and tenant protections require their own review; ADU approval does not settle every rental question. Check with the City before advertising the unit or setting lease terms.
Will fire sprinklers be required?
The City's guidance states that an ADU does not require sprinklers when sprinklers are not required for the primary residence. Other fire and building-safety requirements still apply; have the permit team confirm the requirements for the proposed work.[7]
Plan Your Next Step with Go ADU Construction
You do not need to settle every code question before starting a conversation. Bring your property address, the type of ADU you are considering and what you want the extra space to do for you.
Explore Go ADU Construction's ADU construction services, or contact the team to discuss your project and the next questions to resolve.
This guide provides general planning information, not a property-specific determination or legal advice. Confirm the requirements that apply to your application with the City and your project professionals.
Sources
[5] https://www.energy.ca.gov/programs-and-topics/programs/building-energy-efficiency-standards/2025-building-energy-efficiency - 2025 Energy Code
[6] https://www.energy.ca.gov/programs-and-topics/programs/building-energy-efficiency-standards/energy-code-support-center-12 - 2025 Single-Family Solar PV
[7] https://planning.lacity.gov/odocument/6bf1cc9b-0342-4852-ae4c-646d46953d5c/ZA_Memo_143_Revision_1_Chapter1_8.1.25.pdf - LA ZA Memo 143, Revision 1
[13] https://www.hcd.ca.gov/sites/default/files/docs/policy-and-research/adu-handbook-update.pdf - HCD ADU Handbook, March 2026